Step 3: Jumper setting

Step 4: Download

Fusebits: internal 4MHz clock not divided by 8. Will be good to select the “fast rising power” too. ATTENTION: FIRMWARE IN BETA VERSION. I was not ab...

Did you make a mistake while programming fusebits, or purposely disabled reset pin (RSTDISBL) or ISP programming (SPIEN)? No need to buy or make inconvenient HV programmer only for unlock couple of Tiny AVR’s. This Attiny fusebit HV doctor will cure your dead tiny microcontrollers, by restoring all fusebits to factory settings – nice and easy. Supports all of the serial high voltage interface AVRs, that is 8-pins: Attiny11, Attiny12, Attiny13, Attiny15, Attiny25, Attiny45, Attiny85, and 14-pins: Attiny24, Attiny44, Attiny84. This is very simple and cheap to make, the brain of device is an Attiny2313 uC, couple of resistors and transistors, and a 5V stabilizer. You need 12V stabilized supply for this. Repair begins after the button START is pressed. Button is active again after 250ms, so pressing it will reset device and start a new repair process.

Step 2: How it works

Device uses the High-Voltage Serial Programming (HVSP) to repair fusebits. First of all patient is switched to HV memory programming, then we read signature and check if it’s supported. Then the chip erase is performed if user allows it. Next the lockbits are read, if they not set, patient receives new fusebits, proper for readed model. After that, fusebits are verified, and if they pass the test – this is end of work. If not, doctor will repeat write-verify cycle 10 times, and give up when no success.

I tested Fuse Doctor with a new USB RS232 card and everything works with BASCOM AVR terminal, I found fault with my old card RS232, screen printing of the card was reversed, the RX is marked TX and TX is marked RX.

hello, thank you very much for fuse I built the circuit board version 2h it works perfectly i wass saved 2 ATtiny2313, 1 ATTINY45, 1 ATmega8 (without terminal mode) just with LED it helped me a lot, before I had already tried the method clock 500KHz the input crystal without success.

I use the LED mode because I have not managed to use the terminal mode with any of these microcontrollers.

On your website you give as setting Terminal settings: baudrate: 4800 parity: none databits: 8 stopbits: 1 handshake: none I have an emulator with USB 5-pin RS232 1 TX 1 RX 1 GND 1 +5 V 1 +3.3 V I connect RX TX and GND pins on the 3 pins of FUSE DOCTOR PCB it is recognized as COM7 terminal BASCOM AVR but nothing appears on the screen when I run the reset of the microcontroller while the green LED at the end to let me know that the operation was successful .

Hi, there is no NON-BETA soft. As far as i know, there are problems with attiny15 - so i will try to fix this and give updated soft.

People do not inform me about other problems so i guess everything except this tiny15 is ok - if so, treat next update as non-beta full working :) Without people feedback i can't say that this soft is good or not because i have tested only few of mentioned uC's :)

If you make this circuit and something will be wrong, please contact me and i try to fix the problem :)

Hey there. I recently Build this Project to fix a few Attiny45´s.Everything worked well so far, except for 1 Chip i got.It keeps showing me the Red LED, except when i put the Jumper to the No Signature Position. Then the Red and Green Led keep flashing alternating.What could that mean and could it be possible to fix it?

Its hard to tell what is wrong, signature may be erased. Use Atmega Fusebit Doctor and check what it sends to the terminal, you can easily repair chips with broken signature with this circuit (ver 2.1x)

Can this cicuit be used to repair at mega8 microcontrollers.I have bricked one athrough ponyprog programming its RSTDISBL. Or is there some idea to unprogram RSTDISBL so that ponyprog can detect the chip.

This is true, BUT. It only helps when you set the fusebits as the external clock source, so timer555 or so will generate pulses and you be able to communicate with standard ISP again.

But think what will happen when you set the reset pin as normal I/O or disable ISP communication. Only way to repair fusebits is high-voltage programmer, which not use the ISP and forces reset with 12V and special algorithm :)

Nice project! Any chance on making one for the Atmega16? I've got one that is bricked that I would like to recover at some point. I could probably figure out the schematic part, but I have no programming experience.